Near Field Coupling in Terahertz Metamaterials

Metamaterial is an arrangement of artificial structural elements designed to achieve advantageous and unusual electromagnetic properties. In the unit cell level, metamaterials are composed of an array of small structured elements called split ring resonators (SRRs). Recently, a lot of emphases has been given to the realization of terahertz metamaterials owing to its significance in the construction of terahertz photonic components. In this context, near field coupling in terahertz metamaterials is extremely crucial. The short-range coupling in metamaterials occurs via the electric and magnetic fields due to the close proximity of the neighboring resonators. The electric field mainly couples through the gaps of SRRs, while the magnetic field couples through the circumference. Interaction between resonant elements in metamaterial could result in some novel phenomena and interesting applications that do not exist in conventional uncoupled metamaterials such as the effect of mode hybridization, continues broadband response, etc. Near field coupling in metamaterials either gives the resonance blue shift or red shift, which can be useful in making modulators and frequency tunable devices